See also http://webchick.net/files/presentations/women-in-open-source-owv09-2009-06.pdf
This is probably better answer: http://slatestarcodex.com/2017/08/07/contra-grant-on-exaggerated-differences/
Rough summary (do read the whole thing!): considering that law and medicine achieved gender parity, tech gender gap is likely not due to discrimination, but due to interest.
The PDFs escape me, but Scott Alexander is, as usually, a voice of reason. He has had good writeups on issues like these before, but the this could be you here got me thinking; Maybe tech truly has degenerated into a lost cause and it’s time to move on.